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Discussion Starter #1
It's all stock and original, 1980, 30k on the clock.
ive seen a couple of these stripped down with r6 forks and smaller seats,
and they look great. What do you guys suggest? First thing would be getting it running. It has
been sitting over a year.

 

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Is it possible to convert these to chain drive like they do on the XS1100's? That would make them a more appealing platform.

Also, Triumph Trident (mid to late 90's) carbs are supposed to be the bolt on go fast mod for these motors.
 

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Is it possible to convert these to chain drive like they do on the XS1100's? That would make them a more appealing platform.

Also, Triumph Trident (mid to late 90's) carbs are supposed to be the bolt on go fast mod for these motors.

I know you can use 850 gearing on an 1100 so i would imagine the middle and final drives are near identical, making a conversion possible.
 

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Discussion Starter #5
I thought the shaft drive was kind of cool. It never bothered me on my old guzzi. Do they suck on jap bikes?
Would it make it handle like crap to just leave that part alone? Seems like the ring and pinion outlasts the
average chain and sprocket set, but doesn't offer the option of changing ratios...
I was thinking I'd get a smaller seat and a set of clubmans, and kind of strip it down to start.
As time and money would allow I'd try to adapt some later crotch rocket forks and clip-ons to it. Is there anything wrong with gutting the
stock megaphones until I can afford a 3 into 1?
 

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Not sure about the 750/850's, but the 1100's shaft drive was arguably the worst of the lot of the Jap shafties from the 70's. Lots of shaft jacking and general misbehaviour. I've heard stories of them locking up on more than one occasion (not sure if that's a design issue or just from lack of maintenance). Mind you, the 1100 was pretty powerful motor for it's time so that may have had something to do with the shaft drive unit's failings.

The biggest problem you have is being that it's a Special you have a 16" cruiser style rear rim - which limits your tyre choice and is not very conducive for sharp handling.

Hence the idea of chain drive conversion - that would open up endless wheel choice possibilities.

Anyway, if you're doing it on a budget, sure you can start with cosmetic stuff.....but it's only playing dress-up and you won't really be improving the bike.
 

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jap bikes have horrible shaft jacking.

two words: mad max

That bike will NEVER be "performance" orented so don't go down that road. keep the upright riding position. I like modern suspension on anything so why not go for it. I think your goal should be to make the lightest possible commuter bike you can see how far you can take it. Just don't call it a bobber, a cafe racer, or anything like that. Try to innovate, start something new.

but yeah make it run first.
 

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Discussion Starter #8
I guess 'café ' won't be the right term for this bike, but would it be stupid to change the bars and strip it down? What keeps this bike from ever fitting into the 'cafe' category? I realize it won't be a racer unless I race it, but I have done track days on crotch rockets, and might one day do a vintage track day. There are a few of these around that have been called 'cafe's', and I have always liked the look. The 850 special that Spin Cycle built is pretty much what I have in mind. What does 'shaft jacking' do that I might not like? I understand that it raises the back of the bike under load, but is that really such a big deal? Spin Cycle Industries Yamaha XS850 ~ Return of the Cafe Racers
 

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A real "cafe" racer is an old bike someone has extracted as much performance out of within their means. I have seen this new generation come along and call things "cafe racer" that aren't anything more than a glorified chopper with a set of low bars. It isn't about the look, it isn't really even about the speed (because you can buy a brand new R1 that is more bike than you will ever need), it is about the rewards of mechanical tinkering. Anbody who build an xs850 shaftie and called it a "cafe racer" is just a guy jerking off to an image and a style - it isn't about the bike, it isn't about riding or garage time, it's about feeding his head that he is somehow related to 1950s cool. If you are doing it for a look you are missing the point of the exercise.

Why the 850 is a bad platform:

- heavy. The japanese always straddled the line between the light british and the pig iron americans. They used exotic metals and GP engineering but they overbuilt when they though necessary and it usually means the bike is heavier than it needs to be. Their solution to a bad frame design was to add more tubes, not redesign, if this gives you any idea.

- Shaft drive. It is hard to take a shaftie performance bike seriously. Guzzi's tonti frame does an admirable job as do airhead beemers. But the japanese never intended these bikes to be fast runners, and the shaft jacking is pretty noticable. The good news is it is somewhat predictable, but not something you can eliminate. What shaft jacking functionally does is shorten the wheelbase, which in a turn can change your line. it also changes the suspension rate in the rear because now the shock is fighting the bump and the force of the pinion trying to climb the ring gear.

- suspension. 16" rear wheels are a joke. Chopper bull crap. The forks are too small and inadiquate, and the frame probably has too much rake and too much trail . I believe the stock forks are leading axle which is absolute shit for a performance bike. yeah you can change all this, but not much you can do about the rake on a shaftie without cutting the neck in the frame.

That spin cycle bike is nothing to aspire to. I count quite a few errors and issues. There are some nice parts on there but you can tell they didn't do their homework - it is just a stock frame with some fancy suspension pieces and a a fancy seat.
 

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Agreed it won't ever make a good cafe racer with the emphasis on racer. It can be stripped down, restyled and with a few mods, better suspension and ultimately a bike more fun to ride. That should be the goal, make it yours, make it better and more fun.
 

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Discussion Starter #12
Thanks for the thought. I guess I'll just be chasing the look, then. I've had an r1 and loved it, but now I
have more important things to pay for that a $10k motorcycle. This is just to get me back in the wind,
although I think the stock look of the bike is pretty ugly.
oh well...
 

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Discussion Starter #13
ok, so I have started removing stuff from the bike, and got it running. I am going the route of making it as light as I can, and improve handling the best I can. What would you guys suggest for an inexpensive upgrade? I can't afford a later fork setup just yet, but I did put a fork brace on it already. I also think I will go the route of something like dirtbike handlebars instead of clubmans, and keep the stock controls on it. If it will never fit into the realm of café racers, might as well give up on things that will make it less comfy for the sake of looking cool. I do think I want to cut the rear section of the frame and hoop it, though, for the look of the short tail, and to get rid of that enormous seat and taillight.
 

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If you are really determined to cut the frame, get all other pieces first and make sure the bike is assembled with the custom parts you will use (even if just a mockup). That means if you are planning a wide tire have that already done. This way when you cut and begin to weld you can check for clearance as you go and your finished product can run tighter without guess work.

Most people who put frame hoops on forget this and most I have seen have some clearance issue.
 

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Discussion Starter #15
thank you! that's why I'm here. For a heads up on the little things that I might overlook in my journey toward a better looking/riding version of the machine I have. Should I make my seat before the cut as well? Or do some measuring and make the seat, then make my hoop to fit? does the hoop do much to stiffen the frame, or is it just a way of tying up loose ends that will be exposed by a smaller seat?
 

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thank you! that's why I'm here. For a heads up on the little things that I might overlook in my journey toward a better looking/riding version of the machine I have. Should I make my seat before the cut as well? Or do some measuring and make the seat, then make my hoop to fit? does the hoop do much to stiffen the frame, or is it just a way of tying up loose ends that will be exposed by a smaller seat?
There is usually a "bridge" under the stock seat tying the 2 sides of the upper frame rails together between the shock mounts. This bridge is often cut off when modding frames and the hoop is welded onto the tail to bring the strength back lost from cutting it off. If you are going that route I would do the hoop first and then built the seat to fit.
 

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I thought the shaft drive was kind of cool. It never bothered me on my old guzzi. Do they suck on jap bikes?
Would it make it handle like crap to just leave that part alone? Seems like the ring and pinion outlasts the
average chain and sprocket set, but doesn't offer the option of changing ratios...
I was thinking I'd get a smaller seat and a set of clubmans, and kind of strip it down to start.
As time and money would allow I'd try to adapt some later crotch rocket forks and clip-ons to it. Is there anything wrong with gutting the
stock megaphones until I can afford a 3 into 1?
I personally own a 850 special, and I can tell you that "shaft jacking" is more a myth than a reality. When you accelerate extremely hard, the force on the swing-arm because of the drive shaft will raise the bike's rear end a little. Will you notice it? Probably not. Will you care? Absolutely not. If I was going to do what you're doing, I would get a larger rear wheel from a standard 750 or 850. The tire is smaller so the overall outside diameter will be about the same, but it will look better. Forget about chain drive as its not worth the trouble and especially not worth the price. Now you can get a big bore kit for these that will turn the stock 826cc into a true 900cc engine. That will run you around $400 or so for parts. Swap out the Hitachi carbs for Mukinis, get a 3-1 exhaust, pods for the carbs or even better a single filter like you see in this link... 1980 Yamaha 850
Finally, after you're done cutting up the back and putting you custom seat on it, you can sell me your original seat, as I have need for it. Sign up at Yamaha-triples.org to get more ideas and parts for this bike, and you can PM me over there about your seat.
 

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Depends a lot on the bike. My cb900c is as smooth as a belt or chain. M xs11....pretty bad shaft jack. Especially in town or parking lots.
 

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Depends a lot on the bike. My cb900c is as smooth as a belt or chain. M xs11....pretty bad shaft jack. Especially in town or parking lots.
Most of the complaints I hear about it has to do with the 1100. They have a slightly higher final drive ratio, and with all that engine mass and power it must be noticeable. On a 850, nope. I own a 850 triple and a 650 maxim four cylinder with shaft drive, and I personally don't notice it, or at least care about it.
 

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The seca 650 I had for a while had no lash. That bike with a stage III dynojet did around 120, so made plenty of power, never had handling weirdness or jerky acceleration due to the shaft. Neither did my r75/5, though there was a bit of the bike wanting to lean a bit due to crank positioning, when nailing the throttle.

The monster-torque of the xs1100, I'm sure, makes things a little different.
 
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